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Rising CO2 won't make trees grow more, study suggests

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Re: Rising CO2 won't make trees grow more, study suggests

#41

Post by noselasd »

abootstrapper wrote: post #5

I’ve heard this argument before from climate change deniers. From a laypersons point of view I wonder why would you assume more CO2 makes trees grow more? More oxygen doesn’t make humans grow more, in fact it becomes toxic.

We "assume" that because we can demonstrate it to happen. Place a tree in an enclosure, increase the CO2 level but otherwise keep things the same as outside the enclosure. Trees within the enclosure grows faster than the ones outside the enclosure.

This is not surprising, as we already know trees and plants consume CO2 to produce cellulose and other plant materials.

This is heavily exploited in greenhouses which are CO2 enrichened to produce better yields - albeit used mostly for growing vegetables, not trees.

Re: Rising CO2 won't make trees grow more, study suggests

#42

Post by smokeybear »

mr337 wrote: post #32
justtopost wrote: post #7

Earlier quoted context omitted.

Bingo. While not usually the limiting factor in nature, it can still be a benefit when it is. Just ask all the 1000s of pot growers literally burning propane to produce it indoors and vent it to atmosphere. Grr.

I did not know they did that to produce CO2. Very interesting!

if its done properly excess O2 water vapour heat,and ethane and methane is vented, CO2 is assimilated and effluent atmosphere will have less than atmospheric amounts of CO2.

Re: Rising CO2 won't make trees grow more, study suggests

#43

Post by smokeybear »

mpg33 wrote: post #39

What is the right amount of CO2 to have in the atmosphere scientifically speaking?

between 250-300 ppm is assumed to be an average normal concentration, this is a reference range compared against the observed concentration of a subject plant tissue. This is a scientifically mandated condition with respect to phytophysiological experimentation. These datum are detected with a simple benchtop infrared spectrum gas analyzer. [IRGA] An investigation of extreme rigor, or extreme contention must use instruments of higher accuraccy and selectivity, at great expense of course, and exacting grant proposals as a result.

Re: Rising CO2 won't make trees grow more, study suggests

#44

Post by natermer »

randyrand wrote: post #35

Anecdote: When I artificially inflated the CO2 in my aquarium, my plants grew like BANANAS. Something like 4x the speed, and about 2x as big leaves, etc. It was quite something amazing.

In terms of geologic history the CO2 levels now are lower then they have been. It's not surprising that plants respond very positively to higher rates of CO2.

And it's been proven to be true many times.

I guess what the study is trying to address is the positive aspect of CO2 rising enough to counter the negative aspect of CO2 rising to the plant biomass.

Re: Rising CO2 won't make trees grow more, study suggests

#46

Post by nwah1 »

mrpopo wrote: post #40
saalweachter wrote: post #34

Earlier quoted context omitted.

> For instance, the Saharan desert seems to be greening. I hadn't heard about that, and my first few Googles came back without any good, definitive articles; do you have more information?

It's not. It's a false claim from climate skeptics based on this study: https://www.nature.com/articles/s41467-018-04616-8 The study is about sub saharan Africa, mostly the African savanna, and the identified drivers are human causes (decline in burned area, changes in herbivores density). They explicitly exclude CO2 levels increase as a driver.

>Factorial simulations with multiple global ecosystem models suggest that CO2 fertilization effects explain 70% of the observed greening trend, followed by nitrogen deposition (9%), climate change (8%) and land cover change (LCC) (4%).

https://www.nature.com/articles/nclimate3004

Re: Rising CO2 won't make trees grow more, study suggests

#48

Post by rawland »

hinkley wrote: post #16
nwah1 wrote: post #10

A number of problems with this method of study, and the headline is misleading. The real question is whether there will be more biomass and more photosynthesis in response to more CO2, not whether individual trees grow more. The climate skeptics don't say tree trunks will get wider, they say there will be more plant biomass. And also this is adding in confounding variables and saying more CO2 could change precipitati…

Several of the reports I've seen have said we will get more biomass, but most of it will be plants we generally refer to as weeds.

"It is estimated that between 50% and 85% of the world's oxygen is produced via phytoplankton photosynthesis." Most 'plants' are in the water.

source: https://en.wikipedia.org/wiki/Phytoplankton

Re: Rising CO2 won't make trees grow more, study suggests

#49

Post by maxk42 »

I'll point out that the sunniest parts of western Quebec get fewer than 1900 hours of sunshine annually. [1] That's fewer than any point in the contiguous US. Cedars metabolize O2 -- not CO2 -- in the absence of sunlight. That makes this possibly one of the most biased and possibly misleading selections possible for both location and organism under study.

[1] https://www.currentresults.com/Weather/Canada/Quebec/sunshin...

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